<?php
	class ValidationCode {
		private $width;
		private $height;
		private $codeNum;
		private $image;   //图像资源
		private $disturbColorNum;
		private $checkCode;

		function __construct($width=80, $height=20, $codeNum=4){
			$this->width=$width;
			$this->height=$height;
			$this->codeNum=$codeNum;
			$this->checkCode=$this->createCheckCode();
			$number=floor($width*$height/15);
			
			if($number > 240-$codeNum){
				$this->disturbColorNum=	240-$codeNum;
			}else{
				$this->disturbColorNum=$number;
			}

		
		}
		//通过访问该方法向浏览器中输出图像
		function showImage($fontFace=""){
			//第一步：创建图像背景
			$this->createImage();
			//第二步：设置干扰元素
			$this->setDisturbColor();
			//第三步：向图像中随机画出文本
			$this->outputText($fontFace);
			//第四步：输出图像
			$this->outputImage();
		}
			
		//通过调用该方法获取随机创建的验证码字符串
		function getCheckCode(){
			return $this->checkCode;
		}

		private function createImage(){
			//创建图像资源
			$this->image=imagecreatetruecolor($this->width, $this->height);
			//随机背景色
			$backColor=imagecolorallocate($this->image, rand(225, 255), rand(225,255), rand(225, 255));
			//为背景添充颜色
			imagefill($this->image, 0, 0, $backColor);
			//设置边框颜色
			$border=imagecolorallocate($this->image, 0, 0, 0);
			//画出矩形边框
			imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $border);
		}

		private function  setDisturbColor(){
			for($i=0; $i<$this->disturbColorNum; $i++){
				$color=imagecolorallocate($this->image, rand(0, 255), rand(0, 255), rand(0, 255));
				imagesetpixel($this->image, rand(1, $this->width-2), rand(1, $this->height-2), $color); 
			}

			for($i=0; $i<10; $i++){
				$color=imagecolorallocate($this->image, rand(200, 255), rand(200, 255), rand(200, 255));
				imagearc($this->image, rand(-10, $this->width), rand(-10, $this->height), rand(30, 300), rand(20, 200), 55, 44, $color);
			}
		}

		private function createCheckCode(){
			$code="23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKMNPQRSTUVWXYZ";
			$string='';
			for($i=0; $i < $this->codeNum; $i++){
				$char=$code{rand(0, strlen($code)-1)};
				$string.=$char;
			}

			return $string;
		}

		private function outputText($fontFace=""){
			for($i=0; $i<$this->codeNum; $i++){
				$fontcolor=imagecolorallocate($this->image, rand(0, 128), rand(0, 128), rand(0, 128));
				if($fontFace==""){
					$fontsize=rand(3, 5);
					$x=floor($this->width/$this->codeNum)*$i+3;
					$y=rand(0, $this->height-15);
					imagechar($this->image,$fontsize, $x, $y, $this->checkCode{$i},$fontcolor);
				}else{
					$fontsize=rand(12, 16);
					$x=floor(($this->width-8)/$this->codeNum)*$i+8;
					$y=rand($fontSize+5, $this->height);
					imagettftext($this->image,$fontsize,rand(-30, 30),$x,$y ,$fontcolor, $fontFace, $this->checkCode{$i});
				}
			}
		}

		private function outputImage() {
			if(imagetypes() & IMG_GIF){
				header("Content-Type:image/gif");
				imagepng($this->image);
			}else if(imagetypes() & IMG_JPG){
				header("Content-Type:image/jpeg");
				imagepng($this->image);
			}else if(imagetypes() & IMG_PNG){
				header("Content-Type:image/png");
				imagepng($this->image);
			}else if(imagetypes() & IMG_WBMP){
				header("Content-Type:image/vnd.wap.wbmp");
				imagepng($this->image);
			}else {
				die("PHP不支持图像创建");
			}
		}

		function __destruct(){
			imagedestroy($this->image);
		}
	}


